In aesthetic body contouring, it is sometimes desirable to transfer fat tissue from one portion of the body where it is excessive, unwanted, or unsightly, to another portion of the body where that same fat may be considered more appropriate or appealing. For instance, fat may be removed from a patient's abdominal, hip, or thigh region; it may be desirable to transfer this fat to the buttocks, breast, or bicep region, depending upon the patient. The transfer of fat from one region of a patient's body to another is commonly termed Autologous Fat Transfer or AFT.
The most common approach to fat removal is liposuction, which first involves the infiltration of fluid into a selected region of the body. The infiltrated fluid, comprising primarily a saline solution with an anesthetic (typically lidocaine) and a vasoconstrictor (typically epinephrine), serves several purposes. The bulk saline solution serves to expand the fat tissue away from the connective matrix and provide a more conducive fluid condition for fat removal; the lidocaine reduces pain and patient discomfort (even when the patient is fully sedated and unconscious for the procedure); the epinephrine constricts the blood vessels, thereby reducing bleeding and lidocaine removal, and reduces swelling. Once the infiltration fluid has been introduced, the fat/fluid mixture is removed using a vacuum cannula. The cannula may also be mechanically actuated to assist in the removal; there may also be an intermediate step of applying ultrasound energy to the fat tissue (Ultrasound Assisted Lipoplasty or UAL) in order to fragment or emulsify the tissue to separate it from the connective tissue matrix.
The amount of fluid infiltrated into the patient is typically equal to, or more than, the expected amount of fat to be withdrawn. When the fat is removed by liposuction, it is in a lipoaspirate that includes remnant infiltration fluid, blood and other unwanted connective tissues. In this form, it is unsuitable for reinjection into the patient. A separation means must be provided to separate the wanted fat component from the overall lipoaspirate fluid before the fat component is reinjected into a patient.
To the extent possible, it is desirable that the process of harvesting, separating, and reinjecting take place under conditions approaching “aseptic,” in order to prevent introduction of unwanted infectious or otherwise harmful material into the patient. The harvesting procedures have been well established, and the reinjection approaches have also been demonstrated, however the separation techniques have received less focus and provide an area to improve the overall AFT process.
A number of approaches have been attempted to solve the separation process issues. In the simplest approach, the lipoaspirate is allowed to sit in a harvest container for a period of time. The fat component, being less dense than either blood, freed oils, or saline, eventually floats to the top region of the container where it can be “decanted.” This process however takes a relatively long amount of time, and the separation is rarely complete in that much of the fat remains in intimate mixture with the other components of the lipoaspirate for a period of time that is longer than the patient can safely remain under anesthesia.
Another method involves pouring the lipoaspirate into smaller centrifuge tubes, and centrifuging for a period of time (typically 3 minutes). This process more completely separates the fat cells from the other fluids. The centrifuge tubes can either be decanted into syringes, or, in some systems, capped syringe tubes are used within the centrifuge, eliminating one step in the process.
Another method involves pouring the lipoaspirate through a metal filter, capturing the fat in the filter. The fat is then manually scooped into syringe tubes.
Yet another method involves pouring the lipoaspirate onto a sterile absorbent pad (a “Telfa” pad), and manipulating the fat on the pad until the desired amount of fluid has been absorbed and the remaining fat is sufficiently “dry.” This technique has been referred to as “Telfa rolling.”
The above techniques involve exposing the lipoaspirate to the open environment, with manual handling and manipulation. Thus, they all suffer from an increased possibility of biological contamination. Furthermore, they generally are suited to batch operation, not continuous operation, and typically involve only small quantities of fat.
An alternative approach uses a container with a removal port at the bottom of the container, which eliminates the need to decant the fat. Instead, after the necessary settling time, the bottom valve is opened and the (heavier) blood/fluid is drawn off until only the fat remains. The port is then connected to an injection syringe and the fat is transferred for reinjection. A container for use in this technique is available commercially from Sound Surgical Technologies, Louisville, Colo. as the “Origins Lipo Harvesting System” canister.
Another approach involves placing a filter within a lipoaspirate container, such that the fat is captured and the unwanted liquids are conveyed to another (disposal) container. A system that uses this approach is sold by Shippert Medical, Colorado, under the Tissue-Trans and Filtron product names.
Another approach, called the PureGraft (sold by Cytori Therapeutics, Inc., San Diego, Calif.), involves pumping the lipoaspirate into a flexible plastic container with an internal filter. The fat is further processed by the introduction of additional saline solution, with manual agitation of the container. The result of this process is a relatively pure fat cell solution. However, the amount of fat processed is limited to the size of the flexible container, which is less than 500 cc. The PureGraft, as introduced to the market, is a flexible plastic pouch with an internal filter. The agitation is performed by manually squeezing the pouch. The product is therefore a disposable product because it cannot be effectively cleaned, although it may be used twice for the same patient. The design also limits the process to a small batch at a time. The technique does not handle fat removed using procedures such as power assisted lipoplasty (PAL) very well because of the large strands of fat removed in these types of procedures.
The last techniques mentioned above are “closed”, i.e. not exposing the fat to the environment during processing. Nevertheless, these techniques involve “batch” processing. That is, the fat harvesting process must be complete before filling the syringe tubes for reinjection. The batch processing results in a prolonged AFT procedure.
The prior techniques and devices have various shortcomings, including long processing times; limited total fat processing capability; open system exposing the fat to the air; “batch” processing, i.e. a requirement to complete the fat harvesting process before filling the syringe tubes for reinjection.
It is with respect to these and other considerations that embodiments of the present invention have been made. Also, although relatively specific problems have been discussed, it should be understood that embodiments of the present invention should not be limited to solving the specific problems identified in the background.